1. Field of the Invention
The present disclosure relates to Auger electron spectrometry and to electron beam apparatus.
2. Description of the Background Art
When an electron is emitted from a core level of an atom, leaving a vacancy, an electron from a higher energy level may fall into the lower-energy-level vacancy. This results in a release of energy either in the form of an emitted photon or by ejecting another electron. Electrons ejected in this manner are called Auger electrons.
Conventional Auger electron spectrometers include the hemispherical analyzer, the cylindrical mirror analyzer, and the hyperbolic field analyzer. The hemispherical analyzer and the cylindrical mirror analyzer are serial spectrometers where the spectrometer is scanned in order to collect a complete spectrum in a serial fashion. The hyperbolic field analyzer is an example of a parallel spectrometer where a complete spectrum is acquired in parallel fashion.
Auger electron spectrometers traditionally are incorporated into only non-immersion type scanning electron microscopes (SEMs). In such SEMs, the magnetic and/or electrostatic focusing fields are fully contained or nearly fully contained in the objective lens, and the sample is placed in a field-free or nearly field-free region below the lens. In such a spectrometer, the Auger electrons travel in substantially straight lines from the sample, and the spectrometer's collection efficiency is determined largely by the solid angle of the spectrometer's entrance aperture and the spectrometer's take-off angle with respect to the sample surface.